A safety device for a front-loading weapon of the type comprising a mortar barrel having a closed breech end and an opposite open end for launching a mortar projectile. The device includes at least one sensor, configured for mounting adjacent the mortar barrel, for sensing a mortar projectile upon its insertion in the barrel and an electronic circuit, coupled to said sensor, for detecting movement of the mortar projectile past said sensor, thereby to detect the presence of the projectile in the barrel.